Interface arrangements are known to be connected between an Alternating Current (AC) system, often denoted AC grid and a Direct Current (DC) system, like a High Voltage Direct Current (HVDC) system. Such an arrangement typically includes a converter, such as a voltage source converter, for conversion between AC and DC and having a DC side connected to the DC system and an AC side for coupling to the AC system.
For safety reasons an interface arrangement is often connected between two such systems via circuit breakers. This type of connection is for instance shown in US 2008/0084643.
If faults occur in such a DC system or in the interface arrangement, it is of interest to open the DC system from the AC system. This is normally done through opening the circuit breakers. This opening can normally not be performed immediately when the fault occurs, because the current has to be alternating with zero-crossings.
These faults also put a lot of stress on the electronic components used in the converter, like overvoltage and fault current stress. It is therefore of interest to limit this stress applied on the components of the converter caused by a fault.